An objective of the proposed research is (1) to conduct studies of the chemistry of the hormone, human chorionic gonadotropin, (2) to study its biosynthesis to seek any precursor forms and (3) to identify antigenic determinants of the hormone that lead to the development of specific antisera. Another objective is to evaluate various modes of therapy for Paget's disease of bone and to assess the therapeutic potential of dichloromethylene diphosphonate in metabolic disorders of bone. BIBLIOGRAPHIC REFERENCES: Birken, S., Smith, D.L., Canfield, R.E., and Boime, I.: Partial amino acid sequence of human placental lactogen precursor and its mature hormone form produced by membrane-associated enzyme activity. Biochem. Biophys. Res. Comm. 74:106-112, 1977. Canfield, R., Rosner, W., Skinner, J., McWhorter, J., Resnick, L., Feldman, F., Kammerman, S., Ryan, K., Kunigonis, M., and Bohne, W.: Diphosphonate therapy of Paget's disease of bone. J. Clin. Endocrin. Metab. 44:96-106, 1977.